Degradation study of lubricant with cyclotriphosphazene moiety under low-energy electron impact

When subjected to low-energy electron (<20 eV) impact, A20H lubricant was found to form ammonia or phosphoric acid droplets on the surface of the disk under appropriate temperature and humidity environment. The degradation mechanism was studied by time-of-flight mass spectroscopy and X-ray photoelectron spectroscopy. The side arm (O-C₆H₄-CF₃) attached to cyclotriphosphazene moiety of A20H lubricant and the end group (CF₂CH₂OH) were found to be easily segregated at low electron dosage. PN core (CF₂CH₂OP₃N₃) breakdown occured at higher electron dosage. NH₂/PO species which were formed from the PN core breakdown could be the most probable source of the corrosive droplets.